1. Field of the Invention
The present invention relates to composite materials comprising metal sheathed ceramic fibers.
2. Description of the Related Art
In our co-pending published patent application GB2219006A there is disclosed and claimed a method of reducing the diffusion of defined metals into silicon carbide fibers when making a composite structure, which comprises the covering of the fiber with a contact coating of one of the metals defined therein and then covering the metal with a coating of an oxide thereof.
The method claimed by the invention in GB2219006A was an improvement over the prior art, but some diffusion still occurs. It has been found however, that now, the diffusion is not of the kind where there is interchange of atoms across the interface between the differing materials, which if it were, would result in an alloy consisting of the metal and silicon carbide; rather, the metal diffuses into the grain boundaries of the silicon carbide.
The present invention seeks to further improve the method of forming a composite material from a defined metal or its alloys and ceramic fibers.